924Board.org

Kevin D · Joined: 28 Jul 2005 Posts: 152 Location: Boise, ID

Well I am finally trying to sort the tach. Problem is, I can't read an electrical diagram past "the green wire goes to the #13 post". I have the stock wiring harness and tach from my 924s, but I need to get it to talk with the 968 brain. Does anyone know what wires I'll need to jump?
_________________
'88 924S 3L 6sp RedRat
'92 Duc 900ss
'02 Duc 998 Carbon
'72 RD 350

Paul · Posted: Fri Oct 12, 2007 12:31 pm Post subject:

How about swapping out the tach with one from an early 924 that uses the coil for a signal? I can send you one to try (maybe you have a 931 tach in your spare parts bin?).
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Kevin D · Joined: 28 Jul 2005 Posts: 152 Location: Boise, ID

Yeah, I think I do actually. If I remember correctly...I have the green faced guages from the 931 still. I'll take a look. I saw the PO already pulled a wire through the firewall from the coil. Maybe that is what he was thinking.
_________________
'88 924S 3L 6sp RedRat
'92 Duc 900ss
'02 Duc 998 Carbon
'72 RD 350

Kevin D · Joined: 28 Jul 2005 Posts: 152 Location: Boise, ID

I found the old guages. The green tach from the 931 has just three terminals on the back. They are labeled from left to right...
1: 12
2: 1
3: -

I assume I just need to run a switched 12volt line to the "12" post, the signal line from the coil to the "1" post and the ground from the "-" post.

If this is correct, from which post do I take the signal from the coil?

Last question: Anyone seen green faces available for guages? I'd like to make the rest of my guages match.
_________________
'88 924S 3L 6sp RedRat
'92 Duc 900ss
'02 Duc 998 Carbon
'72 RD 350

Paul · Posted: Fri Oct 26, 2007 12:08 pm Post subject:

I'd try running a wire from "1" to the negative post of the coil.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Sun Oct 28, 2007 1:54 pm Post subject:

Any luck?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Kevin D · Joined: 28 Jul 2005 Posts: 152 Location: Boise, ID

Got distracted with swapping the turbo clock green face to my current clock. I have the lead on the negative terminal at the coil and the wire is pulled through to the gauge pod.
I should have the tach in tomorrow. I am also putting in an MP3 stereo and sub-woofer amp while I am putting down the new carpet....I ran in to a whole lot of "while you are at it"s.
_________________
'88 924S 3L 6sp RedRat
'92 Duc 900ss
'02 Duc 998 Carbon
'72 RD 350

Paul · Posted: Sun Oct 28, 2007 11:42 pm Post subject:

I'm not sure the tach will work, this is only an experiment, so I would just wire if up somewhere near the coil.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Kevin D · Joined: 28 Jul 2005 Posts: 152 Location: Boise, ID

No worries. It's all good. I found an nice switched 12v source, did a clean splice, used the extra ground pigtail from the lights and it all works.
Thanks for the help, Paul!
Now to find the short in my low beams......
_________________
'88 924S 3L 6sp RedRat
'92 Duc 900ss
'02 Duc 998 Carbon
'72 RD 350